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So would that be pure, or almost pure, fine carbon powder? Or are there binders and other stuff in there as well? Powdered graphite found in hardware stores to lubricate locks is pretty pure as far as I know. And cheap as well.

It is easy to make lampblack like Edison did for his experiments. He just put a piece of metal over a candle and took the powder that gathered there. This might be a bit time consuming to get a decent quantity but, you could have several candles and plates going at the same time. Just a thought. This would be something almost everyone in the world could do without special materials or suppliers. (Like those of my graphite powder for locks) Candles are pretty readily accessible all over the world.

Well, after reflexion I think it's a good solution for emergency purpose.

But for third world power supply I am very worried to imagine thousands or more people throwing daily their aluminium oxide/hydroxide in the environment !!

For example if I bring the concept to the Mekong delta, where people have no light in their houses, it would be a cheap solution, but they would throw the electrolyte in the nature ...I was thinking of the millions of people living in house boats in Vietnam and Cambodia, among the poorest people I have seen in Asia.

Hi Bill,yes, you can get it from candles.But you really have to check the resistance of the powder.

Mine bought from the painterÂ´s brand "guardi"has a resistance of around 30 to 50 Ohms when you put aOhmmeter directly into the powder and have the probe tipsaround 2 to 5 millimeters away from each other.

This is a very good nice low value and if youtry it with other graphite powder, just let me know,which one has the lowest electrical resistance.

We need to find the best carbon based powder, that hasthe lowest electrical resistance.

Charcoal is very very poor in electrical resitance andmy guardi lampblack had the lowest resistance I have found so far, so I use this one.

My bought real graphite powder , which I bought fromEbay had more resistance and was more expensive.

To generate your own lampblack from burning candlesit would be preferred to really heat the black powder then reallyhot, as only a really hot temperature willproduce conductive lampblack, lower temperature willNOT make the lampblack conductive, so you really need hot flames !

Another good conductive graphite type is:Russverkollerung or Rebenscharz.

So would that be pure, or almost pure, fine carbon powder? Or are there binders and other stuff in there as well? Powdered graphite found in hardware stores to lubricate locks is pretty pure as far as I know. And cheap as well.

It is easy to make lampblack like Edison did for his experiments. He just put a piece of metal over a candle and took the powder that gathered there. This might be a bit time consuming to get a decent quantity but, you could have several candles and plates going at the same time. Just a thought. This would be something almost everyone in the world could do without special materials or suppliers. (Like those of my graphite powder for locks) Candles are pretty readily accessible all over the world.

But for third world power supply I am very worried to imagine thousands or more people throwing daily their aluminium oxide/hydroxide in the environment !!

Well using cheap solar cells you can reacharge during the daylight the graphitepaper-alufoilcells several times and thus prolong the livecycle of the alufoil.So less alufoil is needed.But you are surely right, that the aluminium-oxid-hydroxid is probablydumped into the rivers and I have to research how dangerous and toxicthis it.Regards, Stefan.

It depends which PH-value the river water has and if the PH-Valueis about 5.0 to 5.5, so a bit acid,then it can affect fish breathing, so yes, this could impact the fishesin the river, but only if the PH value of the water is at that value.

Hi Stephan,Thanks for searching deeply.I understand that you are more looking for a rechargeable battery, and that's a good idea !!Aluminium is much lighter than lead Of course we can't use NaOH in a rechargeable configuration, it would eat the aluminium.

Hello,A quick update on my aluminium battery.I put two silver electrodes with 2 pieces of aluminium foil in water with salt and NaOH to see what it does. So it's 2 cells in series.This first trial gives less power than 1 silver/magnesium ribbon cell.So I have many things to modify after this first trial.I want to reproduce the experiment by the Hong Kong student in the file given by Mk1.NaOH is eating the aluminium slowly, hydrogen bubbles evolve in the liquid.After just a few minutes the light goes down, and if I shake a bit the cells, light comes back for a few seconds. I am really far from the results in the Hong Kong experiment I will keep you informed. I am waiting for graphite pencils to make electrodes as in the pdf.Now I am using a bifilar from a Bedini setup to make a more efficient Joule Thief. I still don't have a toroid.

I would need to press about 10 x 10 cm areagraphite powder directly onto a stainlesss steel mesh,that is also around 10 x 10 cm big in surface area.

This way using no binder, you will have the best and lowest resistanceand the stainless steel mesh will push up the amps from your batteryand lower the electrode resistance.

So I need to find a good solution to this,so that I could do this at home with some easyobtainable tools.I would need to have about 1 mm height below and abovethe stainless steel mesh of pressed graphite powder ( Lampblack for instance).

Any good ideas to do this ?Maybe also just 2 x 50 cm size will work, so I would onlyneed a pressing width of 2 cm ? ( and then do several compression pressing steps toachive the 50 cm length ? 2 cm x 50 cm would also be 100 square cm )

Of course it depends how good the graphite will stay on the stainless steelmesh after several usages and does not come loose from it, when you washthe electrodes after several usage cycles.. so maybe the acryllic bindermethod is stll the preferred method for longer usage cycles ?

Hello Stefan,I read on wikipedia that they use to bake the graphite/clay mix to make the pencils.http://en.wikipedia.org/wiki/PencilExtracts:- Most pencil cores are made of graphite mixed with a clay binder.- Residual graphite from a pencil stick is not poisonous, and graphite is harmless if consumed.- mixing powdered graphite with clay and forming the mixture into rods that were then fired in a kiln. By varying the ratio of graphite to clay, the hardness of the graphite rod could also be varied.

I thought they were just pressing the powder into forms, but it needs to be fired to get the best material ... making things more difficult.

Hi Stefan,Resistance on my graphite pencils are around 20 Ohms.While the best I could get with graphite powder + binder, was around 10 to 15 kilo Ohms !That's 1,000 folds the resistance of the industrial pencils (those that are baked with clay).Hope this helps.